NJAS Wall Posting

NJAS Member Wall Postings and Comments

Often used in audio, but rarely explained...
Wikipedia FPGA Article
The Field Programmable Gate Array, or FPGA, is something you hear a lot about in audio circles, either with something digital like DACs, or sometimes with amplifiers. While a "Gate Array" is a series of selectable logic circuits, like AND, OR or NOR gates (basically transistors that handle logic commands), "Field Programmable" means you can alter the behavior of the circuit itself after it is manufactured. This is a lower level of generality than you get with a CPU inside of a computer, since any CPU comes with a fixed instruction set that any software built on top it (in resident memory) would have to obey. FPGAs, at least in their basic form, allow one to create what are essentially custom CPU chips on the fly (or, more likely, a custom microcontroller). This is a less expensive option than fabricating ones own chips, and has the flexibility to be altered later if necessary. One of the main uses for FPGAs therefore is in prototyping. Each FPGA design essentially becomes a CPU with its own I/O instruction set, but no resident memory. However, they rarely get to a level of generality that computer CPU's have, often designed to complete a relatively basic set of operations. They can be very fast and have high I/O.

Modern FPGAs are more of a hybrid that lands between the raw basic designs of old and a modern CPU, as this makes them easier to program. Since the great expense is in the programming, and since the skills involved are highly specialized, making the easier to program lowers the cost of using them. However, the true FPGA will still allow programming at the gate level. A lot FPGA programming solves the same problems over and over again, so these are often built-in ahead of time to save the hassle.

For any manufacturer, the decision to use an FPGA comes down to the cost/benefits over the total sales. If sales are high enough, then custom chip fabrication is warranted. If it lands in the FPGA sweet spot you pick those, and at the low end you would pick a standard microcontroller/GPU/CPU approach. GPUs are used to mine bitcoins, for example, because they have enough parallelism and memory in combination to be better than FPGAs for mining, and they are available at lower cost and greater numbers.

An audio manufacturer can buy FPGAs and use them for their entire product line to spread out the cost. For example, on DACs at various price points, but the higher priced units might use more than one, or make improvements elsewhere in the circuitry to justify the costs.

FPGAs are not priced at the hobbyist level yet, so for personal use the closest relative might be something like an Arduino board. Also, the learning curve for Arduino and things like the Raspberry Pi I/O boards is much lower. However, they aren't good enough to create anything like your own DAC or ADC. In theory, you could hook up stacks of $5 computers on a stick devices to make your own FPGA, but getting them to talk together reliably and powering them would be an enormous challenge. Any audio device that uses on shows the designer was pretty serious about research and development, and they wouldn't be found in mainstream playback devices from say Sony or NAD.

For those who don't want to rip your own CDs
Progressive Labs
At $1.00 per CD, it seems reasonable. If you are too busy to do it yourself, or too intimidated by the process, this service will load your CDs with metadata in any one of a variety of formats onto a hard drive you provide or purchase from them. All you do is connect the hard drive to your computer or music server, choose a streaming app, like the free Foobar2000, connect your computer or server to your USB DAC, and you are off and running. (I have no connection to Progressive Labs.)

gets kicked out of audiophile society
High-End Mischief — Again!
http://www.realhd-audio.com/?p=6236
Comments:
§ Victor - Much ink has been spilled on the pitfalls of "double-blind" testing. Not that Waldrep doesn't have a point, but it makes the case for in-home demos. Store demos have always been only a starting point of limited value.
⤷ posted Jul 12, 2018
§ Phil,
I have to disagree with the store demo quote. I have never had a store let me do an in home demo. Double-blind testing is a well used methods for drugs and other scientific trials. But things like audio, food and wines are far more subjective and unless some extreme mathematical precision is required (objective) I find that the work involved for double blind testing is not usually justified. In these cases it usually gets down to whether you 'like" something or not. The point is whether you hear a difference in two boxes or not. Whether I see a Bryston Amp or a Belles amp or I don't see them, it makes no difference in my opinion of them or whether I like one more than the other. Now if you are asking me to break down all the data differences that falls into the objective realm. Regarding my wine comment, could I tell the difference between a Chateau Latour vs. a Chateau Lafite whether I see them or not, no. But if you give me a Washington State Cab with one of aforementioned wines, I could tell one from the other. It also depends on how interested you are in sound, to note differences. I happen to be interested in both for a long time.
⤷ posted Aug 3, 2018

I have an old Definitive Technology PF-15 subwoofer that I use only for the LFE signal from my surround receiver. Lately, the volume pot has been acting up. Sometimes, there will be no signal at all. When I turn it a bit, I can usually get a spot where the signal is restored. Any suggestions on how to safely clean this pot or fix it without opening up or removing the plate amp? Thanks!
Comments:
§ Yes. Call me
Izzy
⤷ posted Jul 3, 2018

Hobbyist haven Greenbrook Electronics is no longer in Greenbrook! It has moved east about four miles to North Plainfield, now occupying its own building not too far from Sipersteins paint store and Gertrude Hawks Chocolates. They've consolidated their old store and two warehouses into one giant and roomy showcase. It would probably take an hour to wander around all the aisles. They could use better lighting though. It's much less convenient for me, now, but maybe not for you. If you have any useful info or tips about this move, please leave a comment below.

Highland Park Full Volume Single Malt
Highland Park Full Volume
I have actually had some of this whisky, although not one with the 7" vinyl record included. Not bad at all for this type of Scotch. Here's another review, with better pictures of the box and the story behind it: http://www.scotchmaltwhisky.co.uk/highlandparkfullvolume.htm

Project Audio Systems Buys Musical Fidelity
Comments:
§ And they apparently also bought Music Hall as well.
⤷ posted May 15, 2018

Statement from Shure
First Oppo Digital, now Shure. Hmm. Hat tip to Jack Walton.
Comments:
§ The hipster vinyl fad might be coming to an end.
⤷ posted May 3, 2018 by JimOfAllTrades
§ The "fad" may be fading, but most of the cartridge makers do not cater to the Crosley turntable buyers. In the high end world, cartridge makers have proliferated, and if one of them is not refreshing their line, as well as moving upscale with "reference" and "statement" models, they will die. That was Shure's issue. While some of the old names grew - Audio Technica, Ortofon, et. al., some stagnated and died - Stanton, for example. Shure, rather than doing anything to stay relevant, cut models and stayed away from moving into more high-end models. They allowed their cartridge business to become marginalized and dwarfed by their other product areas, like the exploding headphone business and pro sound gear. At this point, it was natural to exit the space altogether.

But saying vinyl is over because Shure stopped making pickups is like saying digital is over because Oppo stopped making DACs and BD players. Just sayin'.
⤷ posted May 3, 2018
§ Â§ Hipster? I can't see anyone here label me a hipster. Maybe a Luddite between my LP's and Tubes. I just checked the market, the ultimate decider, no? Jerry Raskin shows 213 phono cartridges and only 5 of them are made by Shure. I don't think that Shure's departure will make much of a dent in the vinyl fad. :)
⤷ posted May 18, 2018

You Can Open Up Cases!
FTC on Illegal Warranty Restriction Stickers
If you don't believe that article, here's Popular Mechanics

https://www.popularmechanics.com/technology/gadgets/a19745063/void-if-seal-broken-gadgets-illegal-right-to-repair/

Essentially, if a company provides a warranty on an electronic device (they are not required to do so), your attempts to have the device repaired by yourself or other services will not void the warranty--as a matter of law--this overrides the company's policy. You can even modify a product, and if that modification does not cause the issue under warranty then it's still under warranty. Again, this is a matter of law--it doesn't matter what the seller claims.

Now enforcing the law is sometimes a pain, but there are civil and criminal liabilities, so companies need to be careful how cavalier they are about flouting it. I'm sure they will make up any excuse not to service a device that would fall under this law, but there are civil penalties for lying about the law. Whether it's worth the hassle is always debatable, but that's true for any warranty work. Generally, warranties help sell products but don't bring in any additional cash, unless they are "extended" kind you pay for. So companies often lose money on them. The initial warranty period is often very short, and the paid extended warranty is three years. However, this is up to the company--they are just obligated to honor it once the sale is made and they are still in business. Other restrictions on warranty variations are a matter of state law, in general. What we're talking about here is federal law and applies anywhere under US territory.

Book Questions Use of Theories Not Based on Evidence but Beauty
Link to Ars Technica Book Review
It might seem esoteric, but as a follow-up to my article in the March newsletter, I found a whole book on the topic! Essentially, physics has stalled out for lack of evidence against the Standard Model, a work from the 1970's that's been confirmed over and over again--most recently with the Higgs Boson--despite all the pretty theories arrayed against it. As I've said, and the book reinforces, the scientists are still pursuing their theories, despite being nearly wiped out by lack of evidence, entering the realm of good pseudo-science turning into bad pseudo-science. It's an odd coincidence, but a nice one.

only 1 of them is a tweeter -- the other 6 are mids!
Comments:
§ So, how did they sound?
⤷ posted May 24, 2018

Oppo Stopping Production of Famous Products
Oppo Announcement
The term "cutting the cord" has met up with "pulling the plug" since Oppo is calling it quits, apparently. I guess they are victims of the tendency of people to stream Netflix through inexpensive devices like the Roku box, various gaming consoles and assorted offerings from others like Amazon. Plus they are dependent on monopoly video chip manufacturers to handle DRM, etc. All the rules and regulations regarding DRM essentially forced them out of the custom chip business when the 105 came out, killing off their advantage in video performance. Videophiles are buying 8K HDR TV's with 100K contrast ratios to watch compressed Netflix streams at barely 720i. This is like using 50K in audio gear to listen to streamed music at 90K via Spotify, etc. I'm sure more of the story will come out in the next few months. The writing was on the wall a few years back when they could no longer do "region free" players. To further limit customer choice, almost all disc players come with captured power cords so that you can't get a region 2 player (UK) and use it in the US. Not without a crazy set up involving step-up transformers, etc.
Comments:
§ As has been pointed out, Oppo has one of the top-five best selling smart phones in China. It is likely that the economic scale of their audio products was more of an annoyance than a mainstay. Can you imagine AT&T offering a line of high-end gear?
⤷ posted Apr 9, 2018
§ So what does this mean for manufacturers of other digital players?
⤷ posted Apr 18, 2018

An unbelievable collection of audio equipment eye candy in Yang Jiang City, China
Comments:
§ Victor,
They have ALMOST as much gear as you!
Izzy
⤷ posted Mar 13, 2018